Improved mode of coating and bronzing metals



UNITED STATES PATENT Garrett.

FREDERIO WEIL, OF PARIS, FRANCE.

IMPROVED MODE OF COATING AND BRONZING METALS.

Specification forming part of Letters Patent No. 43,557, dated July 12, 1864.

79 all whom it may concern:

Be it known that I, FREDERIG WEIL, residing at Paris, in the Empire of France, and a c tizen of Frankfort, in Germany, haveinventcd a new and useful Process of Metal-Coating, Bronzing, and ColoringMetals, on which I have already obtained Letters Patent in France on December 11, 1863, Letters Patent in Belgium on February 26, 1864, and Letters of Protection in England on February 29, 1864; and I do hereby declare that the following is a full and exact description thereof.

The nature of my invention consists in a process for metal-coating, bronzing, and coloring metallic articles byimmersing them in an alkaline {solution containing a salt of the metal which is to form the coat, and containing tartaric acid, or any organic matter preventing the precipitation of oxide of said metal, when such solution is used with or without the introduction of zinc, and with or without the addition of cyanure of natron.

To enable others skilled in the art to use and apply my invention, I will now proceed to describe it.

The object of my invention is to cover metals with coats of other metals, so as to puta permanent coat of, say, copper, silver, or other metals on lead, zinc, antimonium, platinum, iron, cast-iron, steel, or other metals or metallic alloys; and, also, if desirable, to put on such metals partially oxidized coats of metals-to wit, partially oxidized on the surface-thereby producing the effects of ordinary bronzing or coloring by means of immersion in the solutions hereinafter to be described.

The ordinary galvanoplastic process is expensive, inconvenient in many respects, difficult of execution, requires for certain metals a preliminary coating with conducting matter, and is in regard to certain metals quite unsatisfactory, causing the coat to adhere to the metal to be coated but very slightly. My new process is free of these objections.

I have found that lead, zinc, platinum, the alloys of lead, zinc, and other metals, when simply immersed at-the ordinary temperature in some alkaline solution of a salt of copper (861 de cm'vrelwith the addition of a tartaric acid, (acid tartariqua) are directly covered with a coat of copper. 0n immersing such metals previously deoxidized in a bath of sulphate of copper dissolved in a strongly-alkalized solution of tartrate of kalinatron (tartratc dc potasse ctdc shade) they become instantly covered with a brilliant and stronglyadhering coat of copper, which can be made of any desired thickness on prolonging the immersion within practical limits. After the coated metal has been removed the same solution may be used over and over again for copper-coating other articles. The solution must be made alkalic by means of any alkali whatever which dissolvesthe oxide ofthemetal to be coatedammonia, for instance. it'zinc is to be coated, or potassa and sodaforlead, at. It must contain any salt of copper whatever and tartaric acid, or any organic matter which prevents the precipitation of the oxide of copper by means of a fixed alkali. The concentration of the solution is of no essential importance, only that on adding more or less water the process will be more or less retarded. For instance, I have found the following solution to answer very well: thirty-five grammes of sulphate of copper; one hundred and seventy-three grammes of tartrate ot' kalinatron (tariratc dc potassa 625 070 soude;) four hundred and eighty cubic centimeters of a solution of caustic soda (soude caustique) of a density of about 1.14; water enough to cause the solulution to measure a liter.

I have found that a solution of a salt of copper and of ammonia only will cover zinc, for instance, with a coat of copper; but-the process above described will be found to be far more perfect and preferable. v

For the purpose of bronzing the metals and producing different colors'on the surface of the metal coats I simply prolong the immersion in the bath described above, only augmenting the relative quantity ofsalt of copper and diminishing the relative quantity of caustic alkali and of alkalic tartrate. Duriugsuch prolonged immersion the copper coatassumes successively tints of bronze, yellow, orange, red, green, blue, gray, black, 850. This effect will be produced in any of my solutions composed on the above stated principles on prolonging the immersion at the ordinary temperature'or on raising the temperature, in which latter casethe process will be hastened. On producing the proper temperature and concentration of the solution the process can be made an instantaneous one, if desired.

1 may remark that tin or tinned iron cannot be copper-coated by immersion in my solution. The tin quickly dissolves and precipitates the copper in the state of protoxide.

For the purpose of coppercoating, bronzing, and coloring iron, east-iron, steel, and certain other metals, the same solution composed on the above-described principle is used, and in the samemam1er,witl1 the only dili'erence that zinc or any equivalent metal must be entered in the solution together with the metals to be operated upon, and that said metals must be in contact with each other, and one of them,at least, in contact with the zinc. The metal coating thus produced is so perfect that no amount of triction will remove the metal coat. A prolonged immersion produces the tints of bronze and colors as above. The su me may be effected by raising the temperature. Presutning that the galvanic z'tction'between the iron and zinc plays a certain part in bringing about this result, the zinc may be replaced by any other material serving a like purpose. A

lronze and other metallic alloys can be coated andeolored by the process first described in the most perfect manner.

For the purpose of silver-coating copper, iron, cast-iron, steel, zinc, lead, antimonium, and other metals, these metals, previously coppered by my above-described process, are

'ner metals may he covered with other metals than copper or silver by immersion in solutions composed upon the same principle.

Having described myinvention, whatlelaim therein as new, and desire to secure by Letters Patent, is-

The process herein described for metal-coating, bronzing, and coloring metallic articles by immersing them in an alkaline solution containing a salt of the metal which is to form the coat, and containing tartaric acid or any organic matter preventing the precipitation of oxide of said metal, when such solution is used with or without the introduction of zinc, and with or without the addition of cyanide of sodium or their equivalents.

FREDERIU VVEIL. In presence of-- E. SHERMAN GOULD, M. O. GRITZNER. 

